The last thing I want is game designers worrying about balance. They need to worry about fun. If it is fun for players in the game, it should stay in the game.
There is, however, a vast amount of DM's who complain about unbalanced things in the game. A lot of complaints about the balance fixes that weren't made for 2024. Even before, you heard (and still hear) a lot of complaints about Feats, Multiclassing, overpowered spells, and more.
So what are we to say to these people? Too bad, game should be fun, the developers have no requirements to balance things? And you can't define "fun"- what's fun for one person is not fun for another, especially when it comes to finding out that your choices in making your character are simply subpar because you chose the wrong race, the wrong class, the wrong subclass, the wrong ASI or feat choices.
Obviously nothing is ever going to be 1:1, but we shouldn't go back to say, 3.5, where the Druid's animal companion was comparable to a Fighter, especially with the powerful beast-only buffs a Druid could apply to it. It may have been fun to be a Bear riding a Bear, shooting Bears, or to play a Planar Shepherd, or to be a Persistent Spell-buffed Cleric who is better than any melee character who has ever existed (save, perhaps, possibly an Ubercharger with Pounce). But it isn't fun for the people who did not choose to play such characters.
And to put all the onus on the DM to figure out, nerf, and ban things that imbalance their games, when again, they are not the professionals who get paid to make such things, is a little unfair. It's asking a lot for all players to be responsible with their character choices, when they may have no idea that they've lucked out and chose the better options, and for every DM to have the experience and judgment to foresee these problems and deal with them beforehand.
How fun is it for a player to build the character they want, only for the DM to nerf them or ban their choices, because it was more than they could handle? And how many DM's really understand what's more than they could handle?
I've played at tables where the DM swore Rogues were overpowered. And who can forget Monkday, when a random person will start a thread expounding the brokenness of Monks, who dodge all the attacks, stun all the things, and are unstoppable at their tables, when so many people have examined the class and found it lacking edition after edition (until, well, now, by all accounts).
To say "WotC should make undead armies possible because that's fun for...well, players who want undead armies" and put it on the DM to say "hahaha, no, not at my table" seems irresponsible on the part of a game designer. And if something gets the reputation for being too good, and it ends up being nerfed or banned at a notable percentage of tables, what good is it, really?
Look at how many people griped about things like the Twilight Cleric, and refused to use it. And how hard is it, if you don't care about balance, to just say, as a DM "animate dead lets you have 12 skeleton warriors, all under your control simultaneously, lasting until they die. Or you lose control and they turn on you, bwahahaha!"
The only thing you can say is "well, not enough DM's would make that choice". Which I think makes my point for me. An option that is only allowed by a few is a waste of space.
All that having been said, I don't see WotC as paragons of balance. That hasn't been their goal with 5e. There's a lot of things that are imbalanced (mostly spells). I despise how they turned magic items from something everyone could expect to find as rewards, to something that DM's are afraid to even put in their game for fear it would destroy things. And worse, forced you to pick and choose between cool, interesting items and stuff that directly increases your power in a wide variety of situations because you can only attune to three items at once.
If they've balanced anything, it sometimes feels like it's by accident. I've long called them the Bethesda of TTRPG's. They put out a broken product, expecting their fans to fix it for them! And somehow, they make money this way! It's a travesty, really.
An experienced DM can make their own rules, their own game, they can mod their own systems. Why on Earth they pay WotC for the privilege of spending all that effort modding their game to make it playable is completely insane.
Anyways, we all know their goal is not to make the best game for anyone. But to keep a large enough percentage of their players happy so they can keep selling their oatmeal that you can flavor for taste, and maybe with enough fruit and brown sugar you can pretend it's not just warm soggy oats.
But given my druthers, I would prefer a game that doesn't come pre-broken, with the option to break it, than one that I may very well be forced to fix, when I'm not being paid to do so.
I mean, when you shell out 50 bucks or more for a damn book, it'd be nice if it wasn't "uh, so, here's busted power creep, use it or don't. Fix it or ban it. We can't be bothered to even explain why we thought this was OK compared to other options".